DEBT (Details) (USD $)	1 Months Ended		3 Months Ended	9 Months Ended
	Sep. 30, 2013	Oct. 31, 2010	Sep. 30, 2013	Sep. 30, 2013	Dec. 31, 2012
Debt
Principal amount outstanding	$ 1,028,822,000		$ 1,028,822,000	$ 1,028,822,000	$ 450,000,000
Unamortized discount	(219,283,000)		(219,283,000)	(219,283,000)	(82,189,000)
Net carrying amount	809,539,000		809,539,000	809,539,000	367,811,000
Equity component of convertible debt issuance, net of tax and issuance costs				113,053,000
Principal amount of the 2017 Notes converted	221,200,000
Convertible Bond Hedge
Common stock covered under convertible bond hedge (in shares)	9,705,442		9,705,442	9,705,442
Exercise price (in dollars per unit)	$ 82.43
Purchase of convertible bond hedge	179,390,000			179,390,000
Warrant Transactions
Number of common stock called by warrants (in shares)	9,705,442		9,705,442	9,705,442
Exercise price (in dollars per share)	$ 96.43		$ 96.43	$ 96.43
Number of trading days over which warrants are exercisable	80 days
Amount received on warrants sold	121,675,000			121,675,000
2018 Convertible Senior Notes and 2020 Convertible Senior Notes
Debt
Aggregate principal amount of notes issued	800,000,000
Number of note series	2
Net proceeds after debt issuance cost	775,600,000
Conversion rate of common stock	0.0121318
Initial conversion price of shares (in dollars per share)	$ 82.43		$ 82.43	$ 82.43
Number of consecutive trading days during which the closing price of the entity's common stock must exceed the conversion price for at least 20 days in order for the notes to be redeemable	30 days
Convertibility of debt, closing price of stock test, percentage of stock price to conversion price that must be exceeded	130.00%
Number of consecutive business days immediately after any five consecutive trading day period during the note measurement period	5 days
Number of consecutive trading days before five consecutive business days during the note measurement period	5 days
Conversion ratio, principal amount	1,000		1,000	1,000
Issuance costs incurred	24,400,000
Equity component of convertible debt issuance, net of tax and issuance costs	5,600,000
Debt issuance costs allocated to the liability components	18,800,000
2018 Convertible Senior Notes and 2020 Convertible Senior Notes | Minimum
Debt
Number of days within 30 consecutive trading days in which the closing price of the entity's common stock must exceed the conversion price for the notes to be redeemable	20 days
2018 Convertible Senior Notes and 2020 Convertible Senior Notes | Maximum
Debt
Convertibility of debt, trading price of debt test, percentage of closing price of stock used in calculation	98.00%
2020 Convertible Senior Notes
Debt
Principal amount outstanding	450,000,000		450,000,000	450,000,000
Unamortized discount	(114,323,000)		(114,323,000)	(114,323,000)
Net carrying amount	335,677,000		335,677,000	335,677,000
Aggregate principal amount of notes issued	450,000,000
Notes stated interest rate percentage	1.875%		1.875%	1.875%
Expected life of debt discount	7 years
Carrying value of equity component	70,500,000		70,500,000	70,500,000
Effective interest rate on liability component (as a percent)	6.40%
2018 Convertible Senior Notes
Debt
Principal amount outstanding	350,000,000		350,000,000	350,000,000
Unamortized discount	(68,784,000)		(68,784,000)	(68,784,000)
Net carrying amount	281,216,000		281,216,000	281,216,000
Aggregate principal amount of notes issued	350,000,000
Number of note series	1
Notes stated interest rate percentage	1.125%		1.125%	1.125%
Expected life of debt discount	5 years
Carrying value of equity component	42,600,000		42,600,000	42,600,000
Effective interest rate on liability component (as a percent)	5.70%
2017 Convertible Senior Notes
Debt
Principal amount outstanding	228,822,000		228,822,000	228,822,000	450,000,000
Unamortized discount	(36,176,000)		(36,176,000)	(36,176,000)	(82,189,000)
Net carrying amount	192,646,000		192,646,000	192,646,000	367,811,000
Aggregate principal amount of notes issued		450,000,000
Net proceeds after debt issuance cost		436,000,000
Conversion rate of common stock	0.0342759			0.0342759
Initial conversion price of shares (in dollars per share)	$ 29.18		$ 29.18	$ 29.18
Number of consecutive trading days during which the closing price of the entity's common stock must exceed the conversion price for at least 20 days in order for the notes to be redeemable				30 days
Convertibility of debt, closing price of stock test, percentage of stock price to conversion price that must be exceeded				130.00%
Number of consecutive business days immediately after any five consecutive trading day period during the note measurement period				5 days
Number of consecutive trading days before five consecutive business days during the note measurement period				5 days
Conversion ratio, principal amount	1,000		1,000	1,000
Notes stated interest rate percentage	2.50%		2.50%	2.50%
Expected life of debt discount				7 years
Effective interest rate on liability component (as a percent)				7.00%
If-converted value in excess of the principal amount of debt				269,600,000
Principal amount of the 2017 Notes converted	221,200,000
Common stock issued on conversion of senior notes (in shares)	7,580,923
Transaction or solicitation fees incurred for the conversion of debt to stock	0
Aggregate loss on conversion			34,600,000
Excess of the fair value of consideration issuable in accordance with the original conversion terms	22,000,000		22,000,000
Difference between the net carrying value and the fair value of the liability component of the principal at the time of each conversion			$ 12,600,000
2017 Convertible Senior Notes | Minimum
Debt
Number of days within 30 consecutive trading days in which the closing price of the entity's common stock must exceed the conversion price for the notes to be redeemable				20 days
2017 Convertible Senior Notes | Maximum
Debt
Convertibility of debt, trading price of debt test, percentage of closing price of stock used in calculation				98.00%